1. Field of Invention
This invention relates to an improved apparatus for a shaped charge.
2. Background of Invention
In the field of explosive devices, it has been the general practice to employ the use of hollow or shaped charges for cutting through or deforming solid material. These charges have wide use in military and non military applications, with the general shaped charge configuration of forming a cavity in the explosive being in use many years. This technique was found to be most effective when the cavity was formed in a conical or cup like shape in the face of the explosive charge. By forming the face of the explosive charge in a symmetrical manner about the axis of the explosive housing or container the explosive force can be controlled to move in a desired direction.
Further magnification of the explosive force can be made by the addition in the cavity of a metal liner. The metal liner is usually formed to have the same configuration as the cavity and is in intimate contact with it. Whenever the explosive charge is detonated a shock wave forms that collapses the liner axially and causes a transmission of energy to the liner causing the formation of a high velocity jet having an enormous amount of energy concentrated in a small area along the axis of the liner.
One of the most critical problems confronting designers of metal moving warheads utilizing an explosively shaped charge has been attempts at acoustic impedance matching by the use of different liner materials. Since each liner material bas a characteristic impedance that affects the propagation of the shock wave, it has been found desirable that the liner impedance be such that the greatest amount to energy is imparted to the liner by the shock wave in order to create the highest velocity jet from the liner material. This will result in an increase in the cutting action of the shaped charge. The disadvantage of impedance matching is that it necessarily requires a complex liner or liners attached to the face of the explosive cavity. These techniques increase the manufacturing costs of the shaped charge and at best only cause a marginal increase in jet velocity resulting in a somewhat better penetrating quality of the shaped charge.